Slide projector

ABSTRACT

This disclosure describes a slide projector having a slide transfer mechanism for moving slides from a slide supply tray, through slide preview and projection stations, to a slide storage tray. The transfer mechanism operates in either a forward or a reverse mode. A pair of yokes are moveable into and out of slide contact in accordance with the setting of face cams. The setting of the face cams is determined by the mode of operation of the projector. During slide movement, the yokes are moved into contact with the slides. While during return movement, the yokes are moved out of contact with the slides.

United States Patent 11 1 Badalich 51 Sept. 4, .1973

[ SLIDE PROJECTOR Primary Examiner-Louis R. Prince [75] Inventor. FrankC. Badallch, Chicago, Ill. Assistant Examinerysteven L. StephanAssigneei p y, g Attorney-Griffin, Branigan & Kindness and William F.Ill. Pinsak [22] Filed. May 10, 1971 I S AC 1211 Appl 141,618 Thisdisclosure describes a slide projector having a v slide transfermechanism for moving slides from a slide 52; us. 353/21, 353/113,353/118, p y t y through Slide Preview and P oj 353 1 tions, to a slidestorage tray. The transfer mechanism [51] Int. Cl. G03b 21/02 Operatesin either a forward a reverse mode- A P [58] Field of Search 353/21,113, l 18, of yokes are moveable into and out of Slide Contact in 3 53131 1 accordance with the setting of face cams. The setting of the facecams is determined by the mode of opera- 5 R f n Cited tion of theprojector. During slide movement, the yokes UNITED STATES PATENTS aremoved into contact with the slides, While during v return movement, theyokes are moved out of contact 2,594,162 4/1952 Hartley 353/113 with theslides 3,l46,666 9/1964 Misuraca 353/104 a 3,656,846 4/1972 Hipelius353/112 23 Claims,'l7 Drawing Figures mmmsar mm $756,717

sum l-UF 7 9Q, Int/72113667": Lg? Funk C. Badalz'ch By @130 Emlyn flyMiss mammw'mn SHEU 2W 7 Fafik CBadaZich suns PROJECTOR BACKGROUND OF THEINVENTION This invention relates to slide projectors and moreparticularly to slide projectors having slide transfermechanisms formoving slides through a projector upon command; the projector includinga slide preview as well as a slide projection station.

Various types of slide projectors have been proposed and are in use.They vary from relatively uncomplicated structures wherein single slidesare manually inserted and removed to complicated structures includingmeans for automatically changing slides each time a trigger switch isactivated.

While prior art projectors have found widespread use, they have variousundesirable features. For example, the uncomplicated structures aredifficult to operate in a normal slide projector environment, i.e., lowlight level conditions, because it is difficult to determine whether ornot a slide is correctly oriented when it is inserted into theprojector.

The more complicated structures have other disadvantages. For example,many of them do not have preview stations. Hence, if a slide is invertedin the slide supply tray, it is projected as an inverted picture. Tocorrect such a condition, it is necessary that the mechanism be reversedand the slide inverted. Other undesirable features of automaticprojectors lie in the mechanism that operates them. In general, thesemechanisms are more complicated than desirable requiring a plurality ofgears and earns operated by a motor. Hence, these mechanisms are subjectto misalignment and failure.

Therefore, it is an object of this invention to provide a new andimproved slide projector.

It is another object of this invention to provide a slide projector thatautomatically moves slides from a slide supply tray, through a slidepreview station and a slide projection station, to a slide storage tray.

It is yet another object of this invention to provide an uncomplicatedand, therefore, reliable slide projector that includes a slide transfermechanism for moving slides through a slide preview station prior toprojection, and operates in a reverse as well as a forward mode.

SUMMARY OF INVENTION In accordance with principles of this invention, aslide projector having a slide transfer mechanism for movingslides froma slide supply tray, through slide preview and projection stations, to aslide storage tray is provided. The slide transfer mechanism includesyokes that are moveable into and out of slide contact positions. When inthe slide contact position, a lateral movement mechanism moves theyokesand slides to the next position". .When out of the slide movementposition, the lateral'movement mechanism only moves the yokes and notthe slides.

In accordance with another principle of this invention, the slidetransfer mechanism can move slides in eithera forward or a reversedirection.

In accordance with a further principle of this invention, two yokes areincluded and rotatably attached to a slide transfer frame. The slidetransfer frame includes a slot. The slot is adapted to interact with apin. The pin attached to a plate which is coupled to a gear. The gearcauses movement of the plate and the slide transfer frame each time arelay is energized. In addition, a second relay controls whether or notthe projector is operating in the forward or the reverse direction.

In accordance with a still further principle of this invention, facecams are'mounted in the projector so as to coact with the yokes. Theface cams cause rotation of the yokes toward or away from the slides inaccor- Moreover, because the system operates in a reverse,

mode as well as a forward mode, a previously observed slide can bere-observed without requiring going through an entire slide tray beforeit can be reobserved.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing objects and many of theattendant advantages of this invention will become more readilyappreciated as the same becomes better understood by reference to thefollowing detailed description when taken in conjunction with theaccompanying drawings,

wherein: I

FIG. 1 is a horizontal sectional view of a slide projector according toa preferred embodiment of the present invention;

FIG. 2 is a cross-sectional view along line 22 of FIG. 1;

FIG. 3 is a cross-sectional view along line 33.of FIG. 1; j FIG. 4 is across-sectional view along line 4--4 of FIG. 1; 7

FIG. 5 is a cross-sectional view along line 5-5 of FIG. 4; I

FIG. 6 is a cross-sectional view along line 6-6 of FIG. 4;

FIG. 7 is a perspective view, partially in section, of a portion of theslide transfer mechanism of the invention; I v

FIG. 8 is a cross-sectional .view along line 8-8 of FIG. 4;

FIG. 9 is a cross-sectional view along line 9-9 of FIG. 4; g

FIG. 10 is a cross-sectional view along line 10 10 of FIG. 4;

FIG. 11 is a cross-sectional view along line 11-11 of H04; f

FIGS. 12A and 12B are cross-sectional views along line 12-12 of FIG. 4for different positions of'the slide transfer mechanism; 5 v j FIG. 13is an enlarged perspective view of a portion of the'slide transfermechanism of the invention;

FIG. 14 is a cross-sectional view along line 14-14 of FIG.6; I f

' FIG. 15 is a cross-sectional view along line 15' 15 of FIG. 4; and,

FIG. 16 is a cross-sectional view along line 16-16 of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT Turning now to the drawingswherein like reference numerals designate like parts throughout theseveral views, FIG. 1 illustrates a slide projector 21 which comprises asubstantially rectangular casing 23 having front and rear walls 25 and27 and side walls 29 and 31. The casing 23 also includes a base 33(FIGS. 2 and 4) and a covering member of top 35. A chamber is thusdefined within the casing 23.

A generally boxed shaped lamp housing 37 is attached to the rear wall 27at a point intermediate the side walls 29 and 31. The lamp housing 37housed a projection lamp 39. A pair of condensing lenses 41 and 43(FIG. 1) are optically aligned with each other and with the lamp 39along a projection axis 45, on one side of a slide track 47. Aprojection lens system 49 is located along the projection axis 45 on theother side of the slide track 47. The projection lens system 49 includesa barrel 51 that extends through the front wall 25. The barrel houses aplurality of lenses 53 (shown schematically by dashed lines in FIG. 1)for projecting a slide image in a conventional manner. The projectionsystem including its lenses, may be of any conventional design, and,accordingly, is not further described herein.

The lamp housing 37 includes an aperture 55 located in one side (theright side as viewed in FIG. 1). Light from the lamp 39 passes throughthe aperture 55 and impinges on a first mirror or reflecting surface 57.The first mirror 57 is fixedly attached to a first mirror stand 59. Themirror stand is fixedly attached by any suitable means, such as bolts61, to the base 33 of the casing 21 so that light from the lamp isreflected by the first mirror 57 along a preview station projection axis63. The preview station projection axis 63 is parallel to the projectionaxis 45 as viewed in FIG. 1. A preview station condensing lens 65 heldin a housing 67 (FIG. 3). is aligned along the preview stationprojection axis 63 on the same side of the slide track 47 as thecondensing lenses 41 and 43 of the projection system.

A preview station projection lens 69 is located on the other side of thetrack 47. The preview station projection lens 69 is mounted in a support71 fixedly attached to the base 33 by any suitable means, such as bolts73 (FIG. 2), so as to project light from the lamp 49 onto a secondmirror 75. The second mirror 75 is attached to a second mirror stand 77which in turn is attached to the base 35 by any suitable means such asbolts 78. The second mirror 75 is mounted at a slight angle to thevertical so as to project light from the lamp 39 onto a screen 81 heldin the top wall 35 of the casing 23 in the manner illustrated in FIGS. 2and 3. As hereinafter described, light from the light source passesthrough a slide located at a preview station and through aslide at aprojection station. A slide is first transferred from the supply, to thepreview station, to the projection station, and to the storage station.Thus, a slide may be previewed prior to its being projected.

Two angle support elements 83 and 85 each having a strengthening ribalong one edge are illustrated in FIG. 1. The angle support elements 83and 85 each have one leg attached to the base 33 by any suitable means,such as bolts 87. The angle support elements are mounted parallel to andnear the sides 21 and 23 so that they can support a generally U-shapedslide transfer mechanism frame 89 at right angles to the projection axisbetween the projection lens system 49 and the condensing lenses 41 and43. The slide transfer mechanism frame 89 generally defines the slidetrack 47.

A slide supply magazine 91, generally in the form of a rectangular opentopped box, has its rear attached to the rear wall 27 and its frontsupported by the slide transfer mechanism frame 89. Similarly, a slidestorage magazine 93, also generally in the form of a rectangular opentopped box, has its back attached to the front wall 25 and its frontsupported by the slide transfer mechanism frame 89. As hereinafterdescribed, slides move from the supply magazine 91, through preview andprojection stations, to the storage magazine 93. Both the supply and thestorage magazines include slide pressure pads 95. The slide pressurepads are generally right angled in cross section and include angularsupport ribs 96. The lower surface of the slide pressure pads rest onthe bottoms of the supply and storage magazines 91 and 93. The upwardlyprojecting surfaces of the slide pressure pads 95 are pressed by theaction of a negator spring 97 against the last or end slide of theplurality of slides that are held in the storage and supply magazines soas to force the slides toward the slide transfer mechanism frame 89.

The negator spring 97 is best illustrated in FIG. 2 and is formed of aflat coiled spring element that is attached to a support member 99. Thesupport member is attached by a bolt 100 to the lower leg 101 of thegenerally U-shaped slide transfer mechanism frame 89. The other end ofthe negator spring 97 is wrapped around a core element 102. Each slidepressure pad includes a rib 103 that projects through a slot 104 in thesupply and storage magazines 91 and 93. The core element 102 is in theshape of a spool and is fixedly attached to a first pin 107 that passesthrough the rib 103. A plate member lies between the lower surface ofthe supply and storage magazines and the core element 102. A second pin109 presses a washer 113 against the lower side of the core element 102.A third pin 111 also passes upwardly through the plate 105 into the rib103 so that alignment is maintained. When the coiled spring is uncoiledby the insertion of slides before the pressure pads, it moves the spooland its attached pressure pad toward the support member 99 whichmovement creates pressure against those slides.

While the invention will operate in either a forward or a reversedirection, the normal or forward movement is from a slide supplyposition 1 15, through a slide preview position 117 and a slideprojection position 1 19, to a slide storage position 121, or from rightto left as viewed in FIG. 4. The mechanism for moving the slides throughthe four positions is best illustrated in FIG. 13. The slide transfermechanism comprises an upper rail 123 having a generally flat uppersurface that is attached beneath the upper side of the slide transfermechanism frame 89 by a plurality of bolts 125 (FIG. 2). The slidetransfer mechanism also includes a slide supply yoke 127 and a slidestorage yoke 129. As hereinafter described, the slide supply yoke movesfrom the slide supply position to the slide preview position 117 andvice versa. The slide storage yoke movesfrom the slide projectionposition 119 to the slide storage position 121 and vice versa.

The slide transfer mechanism further includes a slide transfer frame131. The slide transfer frame 131 includes a relatively long pair ofoutside rails 133 and 135 (FIGS. 12A and 128) closed by a pair of endrails 137 and 139. A pair of inner rails 141 and 143 mounted parallel tothe end rails 137 and 139 intersect the side rails 133 and 135. Aslotted rail 145, longer than the end or inner rails and having a slotin its lower side, bisects the outside rails 133 and 135. As hereinafterdescribed, the slotted rail 145, acts in conjunction with a pin to causethe slide transfer frame 131 to move back and forth or from left toright and vice versa as viewed in FIGS. 12A and 12B.

The slide transfer frame 131 is enclosed by a floor 147 so that a boxlike structure is formed. Preferably, the portion of the slide transfermechanism comprised of the various rails and the floors is formed as aunitary structure.

Mounted beneath the floor 147 and projection outwardly from either sideof the slide transfer frame 131 are a pair of rotatable cams 149 and 151(FIG. 5),). The right cam 149, as viewed in FIG. 5, is a supply cam andthe left cam 151 is a storage cam. The supply and storage cams 149 and151 are pivotally attached to the floor 147 by pins 153. Each camincludes an upwardly.

projecting face cam 155 that is adapted to impinge on either the supplyyoke 127 or the storage yoke 129, in the manner hereinafter described.

Each yoke (FIG. 13) is generally U-shaped and comprises an inside leg157, an outside leg 159, and a cross member 161. The inside leg 157 hasan inwardly projecting region 163 that projects toward the slide in itsrespective slide magazine (either the supply magazine or the storagemagazine, as the case may be). The inside surface of the inwardlyprojecting region 163 is adapted to fit against the inside edge of aslide as illustrated in FIG. when the yoke holds or moves a slide in themanner hereinafter described. The outside leg 159 also includes aninwardly projecting region 165. The inwardly projecting region 165 ofthe outside leg 159 includes an angulated cam face 167 and a notch 169.The notch 169 is adapted to fit about the outside edge of a slide asillustrated in FIG. 12. The cam 167 is adapted to move the remainingslides in a magazine away from the yokes when a slide is moved from thesupply magazine to the preview station or'from the projection station tothe storage magazine. Scratching of the slides by the yoke is preventedbecause the cam 167 impinges on the frames of the slides and not on theimage surface of the slides.

The inwardly projecting region 1650f the outer leg 159 also includes anupwardly projecting finger171.

The upwardly projecting finger 171 fits into an inverted U-shaped sideregion 173 formed in the upper rail 123 best illustrated in FIG. 13. Oneinverted U-shaped side region is formed on one side of the upper rail123 and another inverted U-shaped side region is formed on the otherside of the upper rail 123. The two U-shaped side regions 173 arelocated on opposite ends of the upper rail 123, and are approximatelythe length of the distance between the inner and outer legs 157 and 159of the supply and storage yokes 127 and 129. Located between the outerU-shaped regions 173 is an inner U- shaped region 174 throughwhich theupper portion of j a slide frame passes (FIG. 16). An aperture 176 isformed in the upper rail 123 above the preview station 117 to allow asingle slide to be removed for orientation correction. This aperture 176also allows a slide to be inserted into a series and provides for singleslide projection.

Located beneath each leg and formed as an integral part of each yoke isa flange 175. Each flange projects inwardly and includes an aperture 177having an axis that is parallel with the cross member 161 of the yoke.The apertures 177 of the two flanges of each yoke are axially aligned.Apertures are also formed in each inner rail 141 and each end rail 137of the slide transfer frame 131. The two flanges 175 of each yoke fitoutside an end and an inner rail with one yoke being on one end of theframe and the other yoke being on the other -end of theframe.

Pins 179 pass through the apertures in the end and inner rails and theapertures in the yoke flanges 175 so that the yokes are rotatable withrespect to the slide transfer frame 131 as illustrated in FIG. 13.Preferably, springs (not shown) are included to rotate the yokes aboutthe pins 179 away from their respective supply and storage magazines.The outer flange 175 of each yoke includes a cam follower portion 178that rides on the cam face 155 of the supply and storage cams 149 and151. The interaction between the cam followers and the face cams is suchthat when the supply and storage cams are in suitable positions, theyrotate the yokes toward their respective supply and storage magazines.

Located between the supply and storage magazines is a U-shaped trough181. The U-shaped trough 181 is adapted to hold the lower portion of theframes of thev slides when the slides are in the slide preview station117 and the slide projection station 119. The U-shaped trough 181 andthe inner inverted U-shaped region 174 of the upper rail 123 cooperatesto hold slides in a substantially vertical plane.

The supply and storage cams 149 and 151 are rotated about theirrespective pins 153 by four pairs of control pins 183 (FIG. 5). Thecontrol pins 183 are mounted on the outer ends of inner and outer leverarmsl84 and 185 and project upwardly through apertures 186 in the lowerside of the slide transfer mechanism frame 89 as illustrated in FIGS. 4and 6. The inner lever arms 184 are located adjacent the outer edges ofthe slide preview and projection positions 117 and 119..The outer leverarms 185 are located adjacent the outer edges of the slide supply andstorage positions 115 and 121. By

this location arrangement, the inner lever arms control yoke rotation atthe slide preview and projection positions and the outer lever armscontrol yoke rotation at the slide supply and storage positions, in themanner hereinafter described.

The inner and outer lever arms 185 are rotatably attached by pins 189that pass through slots 190 in a control plate 193. The position of thepins is determined by the right or left position of the control plate193 as viewed in FIG. 6, and the position of the control plate isdetermined by the energization. of a forward-reverse relay 191.. Thatis, the armature of the forwardreverse relay 191 is connected to thecontrol plate 193 so as to move the control plate and attached controlpins 183 to theright or left. When the plate is moved in one di- 1rection, one of the control pins183 of each pair moves inward'and theother movesoutward. Reversingthe direction of movement the control plate193 moves the supply and storage cams 149 and 151, so as to rotate thesupply and storage cams 149 cams 149 and 151, so as to rotate the supplyand storage cams 149 about their respective pins 153 as the yokes aremoved back and forth in the hereinafter described manner.

As the face 155 of the supply and storage cams 149 are rotated, theyinteract with the cam follower portions 178 of the supply and storageyokes 127 and 129. This interaction moves the supply and storage yokestoward or away from the supply and storage magazines for purposeshereinafter described.

In order to maintain vertical alignment of slides in the preview andprojection positions, preview and projection pressure plates 194 and 196(FIGS. 13 and 16) are provided. The preview and projection pressureplates are generally rectangular shaped frame structures having outercammed edges 198 to provide easy slide egress. One pressure plate ismounted on one side of the U-shaped trough 181 and the other pressureplate is mounted on the other side of the U-shaped trough. The pressureplates are attached to the U-shaped trough 181 and the upper rail 123 byspring loaded bolts 200 which pressure the pressure plates toward theU-shaped trough and the upper rail.

The slide transfer frame 131 is moved back and forth by the operation ofa slide movement mechanism best illustrated in FIGS. 6 and 7. The slidemovement mechanism includes a worm 197 mounted on one end of a shaft199. A pulley 201 is mounted on the other end of the shaft and isconnected to a motor 203 (FIG. 1) by a belt 205. The motor 203 alsodrives a fan 207 to provide cooling for the projector.

The worm 197 interacts with a gear 209 mounted in a horizontal planeabout a vertical shaft 211. As illustrated in FIG. 4, the shaft isnon-rotatably attached to the base 33. An indexing collar 213 having aplurality of outer notches 215 is mounted on the shaft 21 1 above thegear 209. The indexing collar is fixedly attached to, or formed as aunitary member of the gear 209. A bearing 214 is mounted between theshaft 211, and the gear 209 and the indexing collar 213. The shaft 211passes through an oval aperture 217 in the control plate 193. Theaperture 217 is located beneath the gear 209. Hence, the control plate193 can slide back and forth with respect to the shaft 211 and itsassociated components when the forward-reverse relay 191 is energizedand de-ener'gized.

Mounted above the indexing collar 213 on the shaft 21 1 is a cylindricalplate 219. The cylindrical plate 219 has an upwardly projecting pin 221that fits into the slot in the slotted rail 145 formed in the slidetransfer frame 131 (FIG. 13). Rotatably attached to the lower side ofthe cylindrical plate 219 is a generally triangular shaped controlelement 223. The control element has a downwardly projecting region 225'that interacts with the notches 215m the indexing collar 213. One end ofa wire spring 226 having a single coil passes through an aperture 227 inthe cylindrical plate 219. The other end of the wire spring 226 passesthrough an aperture 229 in the generally triangular shaped controlelement 223. The generally triangular shaped control element is alsorotatably attached to the cylindrical plate 219 by a pin 224. Thegenerally triangular shaped control element 223 and the wire spring 226are formed and mounted so that the generally triangular shaped controlcan be moved between either of two positions, one position being suchthat the downwardly projecting member 225 is located in a notch 215 andthe other position being such that the downwardly projecting member 225is not located in a notch 215.

The generally triangular shaped control element 223 also has anoutwardly projecting portion 230 adapted to be acted on by upwardlyprojecting portions 231 formed in a pair of right angle arms 233 and 235(FIGS. 6 and 7). The right angle arms 233 and 235 are pivotallyconnected at their junctions to the control plate 193 via bolts 234 andcylindrical separators 236. The right, right angle arm as viewed in FIG.7 has an outwardly projecting region that fits into an aperture in theleft, right angle arm. In addition, the right, right angle arm 223 hasan outwardly projecting element that is connected to the armature of acontrol relay 237. When the control relay 237 is energized, the rightangle arms 233 and 235 rotate about their pivotal points. This rotationmoves one or the other of the upwardly projecting elements 231 out ofcontact with the outwardly projecting portion 230 of the generallytriangular shaped control element. This co-action rotates the generallytriangular member 223 about its pin 224 to move its downwardlyprojecting member 225 into one of the notches in the collar 213. Whichone of the two upwardly projecting elements 231 of the right angle armsinteracts with the outwardly projecting element 229 of the generallytriangular member 223 depends upon whether or not the forward-reverserelay 191 is energized. That is, if the control plate 193 is located inits right position as viewed in FIG. 6,.the upwardly projecting element231 of the left, right angle arm 233 coacts with the triangular controlelement 223. Conversely, if the control plate 193 is located in its leftposition as viewed in FIG. 6 the upwardly projecting element of theright, right angle arm coacts with the triangular shaped controlelement.

Turning now to a description of the operation of the slide movementmechanism heretofor described; assuming initially that the slidemovement mechanism is going to move slides in a forward direction (i.e.,from the slide supply magazine 91 to the slide storage magazine 93), theforward-reverse relay is not energized. Because it is not energized, acoil spring 239 (FIG. 6) wound about the armature of that relay movesthe control plate 193 to its leftmost position. This position of thecontrol plate is illustrated in FIG. 7. In this position, as previouslydescribed, the upwardly projecting element 231 of the right, right anglearm 235 coacts with the outwardly projecting portion 230 of thegenerally triangular shaped control element 223 to rotate the triangularshaped element about its pin 224 and move the downwardly projectingmember out of the notches 215. When the control relay 237 is energizedand the upwardly projecting portion 231 of the right, right angle arm235 moves away from the outwardly projecting portion 230 of thegenerally triangular shaped element 223, the generally triangular shapedelement 223 is then rotated about its attachment pin 224 by the wirespring 226 so that its downwardly projecting member 225 is moved intoone of the notches 215 in the indexing collar 213. When this actionoccurs, the pin 221 is rotated through 360 by the cylindrical plate 219because the cylindrical plate 219 is now connected to the gear 209. Therotation stops at 360 because the outwardly projecting portion 230 ofthe generally triangular shaped element 223 again contacts the upwardlyprojecting element 231 of the right, right angle arm 235 first to theleft and then to the right as viewed in the FIGURES because the pin 221is in the slot in the slotted rail 145. This action continues until acomplete revolution occurs, at which point the outwardly projectingportion 230 of the generally triangular shaped element 223 againintersects the upwardly projecting portion 231 of the right, right anglearm 235. Unless, of course, the control relay has been continuouslyenergized. If so, a second revolution occurs. In this manner, the rotarymotion of the motor is converted into reciprocal slide transfer framemotion.

The foregoing description has described how the slide transfer framemoves reciprocally back and forth, the following description sets forthhow the slide supply and slide storage yokes 127 and 129 are moved intoand out of engagement with the slides in the slide supply and slidestorage magazines. This movement is controlled by the interaction of thesupply and storage cam elements 149 and 151 and the cam faces 178 of theslide supply and slide storage yokes157 and 159. Specifically, becausethe forward-reverse relay is unenergized, the control plate 193 is inthe position illustrated in FIG. 6. Because it is in this position, thepins 183 are in the positions illustrated in FIGS. 5 and 6. That is, thepins 183 of the right outer lever arm 185, as viewed in FIG. 5, rotatethe supply cam 149 in a counterclockwise direction while the pins of theright inner lever arm 184 rotate the supply cam in a clockwisedirection. Because of this cam movement, the suppy yoke 127 is rotatedtoward a slide when the supply yoke is at the supply position 115 andaway from a slide when the supply yoke is at the slide preview position117. On the opposite side of the projector, the pins of the left outerlever arm 185 rotate the storage cam 151 in a clockwise direction whilethe pins of the inner lever arm 184 rotate the storage cam in acounter-clockwise direction. Because of this cam movement, the storageyoke 129 is rotated toward a slide when the storage yoke is at theprojection position 119 and away from the slide when the storage yoke isat the storage position 121.

Because of the just described pin-cam operation, the slide supply cam149 is rotated in a counter-clockwise direction as the slide transferframe 131 reaches the end of its path of travel to the right. Thismovement causes the face cam 155 to impinge on the downwardly projectingportion of the slide supply yoke I27 thereby rotating the slide supplyyoke toward the supply magazine 91. This rotation action is bestillustrated in FIG. 9 as being from the dotted line to the solid linepositions. The movement is such that the slide supply yoke 127 engages aslide between the notch 169 and the inner side of the inwardlyprojecting region 163 of the inside leg 157 of that yoke. Thisengagement is best illustrated in FIG. 12. At the same time and in thesame manner, the storage yoke is moved into engagement with a slide atthe slide projection position. i

At this point, both the slide supply yoke and the slide storage yokeshave moved into engagement with slides the slide supply yoke with thenext slide in the slide supply magazine and the slide storage yoke withthe slide at the projection station. As the gear 209 continues torevolve, the pin moves in the slotted rail and, hence, the slidetransfer frame 131 moves to the left as viewed in the drawings. As thismovemenet begins, the upwardly projecting finger 171 of the slide supplyand slide storage yokes move into the inverted U-shaped slide regions173 in the upper rail 123. The movement to the left continues until theslide storage yoke is in front of the slide storage magazine and theslide supply yoke is in front of the preview station 117. At this point,the supply cam impinges on the pins 183 of the right inner lever arm.This impingement causes the face cam to rotate in a clockwise directionand allows the slide supply yoke 129 to move away from the slide thatthe slide supply yoke has moved to the preview position. In a similarmanner, the storage yoke is moved away from the slide it has moved tothe storage position. This latter movement is illustrated in FIG. 11 asthe movement of the slide storage yoke from a solid line position to adotted line position. It should be noted that the upwardly extendingfingers 171 of the yokes do not prevent rotation because the upwardlyprojecting fingers 171 are beyond the end of the inverted U-shaped sideregions 173 when the yokes are rotated.

When the control relay 237 is again energized, the foregoing cycle isrepeatedand the slide now in the slide preview station 117 moves to theslide projection station. The slide inthe slide projection station movesto the storage magazine and a slide from the supply magazine moves tothe slide preview station 117.

When reverse movement is desired, the forwardreverse relay 191 isenergized. This energization moves the control plate 193 to itsrightmost position. When this occurs, all of the pins reverse theirformer positions and the left, right angle arm 233 impinges on theoutwardly projecting portion 230 of the triangular shaped controlelement 223. This shift is essentially a shift so that when the slidestorage yoke isin front of the storage magazine, it picks up rather thandisposes of a slide. Conversely, when the slide supply yoke 127 is infront of the supply magazine, it drops off, rather than picks up, aslide. Other than these changes, the reverse operation is identical tothe forward operation, hence, it will not be further discussed here.

It will be appreciated from the foregoing description that the inventionprovides a rather uncomplicated and, therefore, reliable mechanism formoving-slides through a slide projector. While a preferred embodiment ofthe invention has been described and illustrated, it will be appreciatedthat various changes may be made without departing from the generalscope of the invention.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. A slide projector comprising:

projection means for projecting slides, said projection means defining aprojection axis;

a supply magazine located on one side of said projection axis forsupplying slides; i

a storage magazine located on the other side of said projection axisfrom said supply magazine for storing slides; and,

a slide movement means for moving slides in a generally vertical planethrough said projection axis from one of said magazines to the other ofsaid magazines in a sequential manner so that slides are projected bysaid projection means when they intersect said projection axis, saidslide movement means including:

i. a supply yoke for engaging and moving a slide into or out of saidsuppy magazine and toward or away from said projection axis in apredetermined manner, said supply yoke including means for pressing thesecond and subsequent slides in said suppy magazine away from saidsupply yoke when a slide is moved into or out of said supply magazine;

. a storage yoke for engaging and moving a slide into or out of saidstorage magazine and toward I or away from said projection axis in apredetermined manner, said storage yoke including means for pressing thesecond and sub-sequent slides in said storage magazine away from saidstorage yoke when a slide is moved into or out of said storage magazine;

iii. yoke control means operatively connected to said supply and storageyokes for moving said supply and storage yokes such that their means forpressing are moved into and out of engagement with the second slide insaid supply and storage magazines, respectively; and,

iv. transfer means operatively connected to said supply and storageyokes for moving said supply and storage yokes back and forth at rightangles to said projection axis so that slides are moved through saidprojection axis as said supply and storage yokes are moved back andforth by said transfer means, and for moving said supply and storageyokes such that their said means for pressing are moved into and out ofengagement when said second slides by said yoke control means as thesupply and storage yokes move a slide into or out of said supply andstorage magazines.

2. A slide projector as claimed in claim 1 wherein said transfer meansincludes a generally rectangular slide transfer frame located beneathsaid projection axis and adapted to reciprocate back and forth beneathsaid generally vertical plane through which said slides move, saidsupply and storage yokes being rotatably mounted adjacent to the ends ofsaid slide transfer frame.

3. A slide projector as claimed in claim 2 wherein said yoke controlmeans comprises; t

supply and storage cams rotatably attached to said slide transfer framebeneath said slide trans-fer frame so as to project outwardlythere-from;

a control mechanism for selectively rotating said supply and storagecams between two positions in a predetermined manner; and,

cam faces formed in said supply and storage yokes adjacent to saidsupply and storage cams so that when said supply and storage cams areselectively rotated back and forth between said two positions by saidcontrol means, said supply and storage yokes are rotated into and out ofengagement with said slides.

4. A slide projector as claimed in claim 3 wherein said slide transferframe includes a rail mounted at right angles to the direction that saidslide transfer reciprocates, said rail having a slot in its lowersurface; and, wherein said slide movement means further comprises acylindrical plate and a rotatable pin mounted on said cylindrical plate,said pin projecting into said slot in said rail so that the rotationalmovement of said pin is changed into reciprocating movement of said railand said frame when said cylindrical plate is rotated, and a drivingmeans for rotating said cylindrical plate.

5. A slide projector as claimed in claim 4 wherein said driving meansincludes a notched indexing collar mounted on a shaft and coupling meansfor coupling said notched indexing collar to said cylindrical plate soas to cause intermittent rotational movement of said cylindrical plateand said pin.

6. A slide projector as claimed in claim 5 wherein said coupling meansincludes:

a relay;

an arm having an upwardly projecting portion, said arm being operativelyconnected to said relay so as to be moved when said relay is energized;and,

a generally triangular shaped control element rotatably mounted on saidcylindrical plate, said triangular shaped control element having anoutwardly projecting portion formed so as to coact with said upwardlyprojecting portion of said arm, and a downwardly projecting portionadapted to fit into said notches in said indexing collar when saidupwardly projecting portion of said arm coacts with said outwardlyprojecting portion of said generally triangular shaped control element,said action occuring when said relay is energized.

7. A slide projector as claimed in claim 6 wherein said cam controlmechanism includes a forwardreverse relay operatively connected to saidsupply and storage cams so as to cause said supply and storage cams torotate, whereby said supply and storage yokes are rotated.

8. A slide projector as claimed in claim 7 wherein said driving meansalso includes a gear mounted on said shaft and coupled to said indexingcollar and and a motor operatively connected to said gear forcontinuously rotating said gear.

9. A slide projector as claimed in claim 8 wherein said coupling meansalso includes a second arm having an upwardly projecting portionoperatively connected to said first arm, said first and second armsbeing mounted on opposite sides of said indexing collar so that theirupwardly projecting por-tions coact with the outwardly projectingportion of said generally triangular shaped control element.

10. A slide projector as claimed in claim 9 wherein said cam controlmechanism also includes a control plate and rotatable lever arms mountedon said control plate, said rotatable lever arms having pins thatinteract with out-wardly projecting portions of said supply and storagecams, said interaction causing said supply and storage cams to rotateintoone of said two positions, said control plate being attached to saidforwardreverse relay so that said control plate and said lever arms forma coupling between said forward-reverse relay and said supply andstorage cams.

11. A slide projector as claimed in claim wherein said slide projectorhas supply, preview, projection and storage posi-tions, said supply yokebeing moveable between said supply and preview positions and saidstorage yoke being moveable between said projection and storagepositions.

12. A slide projector as claimed in claim 11 wherein said lever arms arefour in number, the first lever arm being adjacent said supply position,the second lever arm being adjacent said preview position, the thirdlever arm being adjacent to said pro-jection position, and the fourthlever arm being adjacent to said storage position, said lever arms beingmoveable by said control plate into forward and reverse positions.

13. A slide projector as claimed in claim 1 wherein said slide projectorhas supply, preview, projection and storage positions, said supply yokebeing moveable between said supply and preview positions and saidstorage yoke being moveable between said projection and storagepositions.

14. A slide movement mechanism for moving slides from a first slidemagazine to a second slide magazine and vice versa comprising:

a first yoke for engaging and moving a slide into or out of said firstmagazine, said first yoke including means for pressing the second andsubsequent slides in said first magazine away from said first yoke whena slide is moved into or out of said first magazine; second yoke forengaging and moving a slide into or out of said second magazine, saidsecond yoke including means for pressing the second and subsequentslides in said second magazine away from said second yoke when a slideis moved into or out of said second magazine;

yoke control means operatively connected to said first and second yokesfor moving said first and second yokes such that their means forpressing are moved into and out of engagement with the second slide insaid first and second magazines, respectively; and,

transfer means operatively connected to said first and second yokes formoving said first and second yokes back and forth at right angles tosaid direction of yoke movement caused by said yoke control means sothat said first and second yokes are moved back and forth by saidtransfer means, and for moving said first and second yokes such thattheir said means for pressing are moved into and out of engagement withsaid second slides by said yoke control means as the first and secondyokes move a slide into or out of said supply and storage magazines.

15. A slide movement mechanism claimed in claim 14 wherein said transfermeans includes a generally rectangular slide transfer frame adapted toreciprocate back and forth in a path beneath said first and secondmagazines, said first and second yokes being rotatably mounted adjacentto the ends of said slide transfer frame. g

16. A slide movement mechanism as claimed in claim 15 wherein said yokecontrol means comprises;

first and second cams rotatably attached to said slide transfer framebeneath said slide transfer frame so as to project out-wardly therefrom;

a control mechanism for selectively rotating said first and second camsbetween two positions in a predetermined manner; and,

cam faces formed in said first and second yokes adjacent to said firstand second cams so that when said first and second cams are selectivelyrotated back and forth between said two positions by said control means,said first and second yokes are rotated into and out of engagement withsaid slides.

17. A slide movement mechanism as claimed in claim 16 wherein said slidetransfer frame includes a rail mounted at right angles to the directionthat said slide transfer frame reciprocates, said rail having a slot inits lower surface; and, wherein said slide movement means furthercomprises a cylindrical plate and a rotatable pin mounted on saidcylindrical plate, said pin projecting into said slot in said rail sothat the rotational movement of said pin is changed into reciprocatingmovement of said rail and said frame when said cylindrical plate isrotated, and a driving means for rotating said cylindrical pl'ate.

18. A slide movement mechanism as claimed in claim 17 wherein saiddriving means includes a notched indexing collar mounted on a shaft andcoupling means for coupling said notched indexing collar to saidcylindrical plate so as to cause intermittent rotational movement ofsaid cylindrical plate and said pin.

19. A slide movement mechanism as claimed in claim 18 wherein saidcoupling means includes:

a relay;

' an arm having an upwardly projecting portion, said am beingoperatively connected to said relay so as to be moved when said relay isenergized; and,

a generally triangular shaped control element rotatably mounted on saidcylindrical plate, said triangular shaped control element having anoutwardly projecting portion formed so as to coact with said upwardlyprojecting portion of said arm, and a downwardly projecting portionadapted tofit into said notches in said indexing collar when saidupwardly projecting portion of said arm coacts with said outwardlyprojecting portion of said generally triangular shaped control, saidaction occuring when said relay is energized. Y

20. A slide movement mechanism as claimed in claim 19 wherein said camcontrol mechanism includes a forward-reverse relay operatively connectedto said first and second cams so as to cause said first and second camsto rotate, whereby said first and second yokes are rotated.

21. A slide movement mechanism as claimed in claim 20 wherein saiddriving means also includes a gear mounted on said shaft and coupled tosaid indexing collar and a motor operatively connected to said gear forcontinuously rotating said gear. v

22. A slide movement mechanism as claimed in claim 21 wherein saidcoupling means alsoincludes a second arm having an upwardly projectingportionoperatively connected to said first arm, said first and secondarms being mounted on opposite sides of said indexing collar so thattheir upwardly projecting portions coact with the outwardly projectingportion of said generally triangular shaped control element. I

23. A slide movement mechanism as claimed in claim 22 wherein said camcontrol mechanism also includes a control plate and rotatable lever armsmounted on said control plate, said rotatable lever arms having pinsthat interact with outwardly projecting portions of said reverse relayso that said control plate and said lever first and second cams, saidinteraction causing said flrst arms form a coupling between saidforward-reverse and second cams to rotate into one of said two posirelayand said first and second cams tions, said control plate being attachedto said forward-

1. A slide projector comprising: projection means for projecting slides,said pro-jection means defining a projection axis; a supply magazinelocated on one side of said projection axis for supplying slides; astorage magazine located on the other side of said projection axis fromsaid supply magazine for storing slides; and, a slide movement means formoving slides in a generally vertical plane through said projection axisfrom one of said magazines to the other of said magazines in asequential manner so that slides are projected by said projection meanswhen they intersect said projection axis, said slide movement meansincluding: i. a supply yoke for engaging and moving a slide into or outof said suppy magazine and toward or away from said projection axis in apredetermined manner, said supply yoke including means for pressing thesecond and subsequent slides in said suppy magazine away from saidsupply yoke when a slide is moved into or out of said supply magazine;ii. a storage yoKe for engaging and moving a slide into or out of saidstorage magazine and toward or away from said projection axis in apredetermined manner, said storage yoke including means for pressing thesecond and sub-sequent slides in said storage magazine away from saidstorage yoke when a slide is moved into or out of said storage magazine;iii. yoke control means operatively connected to said supply and storageyokes for moving said supply and storage yokes such that their means forpressing are moved into and out of engagement with the second slide insaid supply and storage magazines, respectively; and, iv. transfer meansoperatively connected to said supply and storage yokes for moving saidsupply and storage yokes back and forth at right angles to saidprojection axis so that slides are moved through said projection axis assaid supply and storage yokes are moved back and forth by said transfermeans, and for moving said supply and storage yokes such that their saidmeans for pressing are moved into and out of engagement when said secondslides by said yoke control means as the supply and storage yokes move aslide into or out of said supply and storage magazines.
 2. A slideprojector as claimed in claim 1 wherein said transfer means includes agenerally rectangular slide transfer frame located beneath saidprojection axis and adapted to reciprocate back and forth beneath saidgenerally vertical plane through which said slides move, said supply andstorage yokes being rotatably mounted adjacent to the ends of said slidetransfer frame.
 3. A slide projector as claimed in claim 2 wherein saidyoke control means comprises; supply and storage cams rotatably attachedto said slide transfer frame beneath said slide trans-fer frame so as toproject outwardly there-from; a control mechanism for selectivelyrotating said supply and storage cams between two positions in apre-determined manner; and, cam faces formed in said supply and storageyokes adjacent to said supply and storage cams so that when said supplyand storage cams are selectively rotated back and forth between said twopositions by said control means, said supply and storage yokes arerotated into and out of engagement with said slides.
 4. A slideprojector as claimed in claim 3 wherein said slide transfer frameincludes a rail mounted at right angles to the direction that said slidetransfer reciprocates, said rail having a slot in its lower surface;and, wherein said slide movement means further comprises a cylindricalplate and a rotatable pin mounted on said cylindrical plate, said pinprojecting into said slot in said rail so that the rotational movementof said pin is changed into reciprocating movement of said rail and saidframe when said cylindrical plate is rotated, and a driving means forrotating said cylindrical plate.
 5. A slide projector as claimed inclaim 4 wherein said driving means includes a notched indexing collarmounted on a shaft and coupling means for coupling said notched indexingcollar to said cylindrical plate so as to cause intermittent rotationalmovement of said cylindrical plate and said pin.
 6. A slide projector asclaimed in claim 5 wherein said coupling means includes: a relay; an armhaving an upwardly projecting portion, said arm being operativelyconnected to said relay so as to be moved when said relay is energized;and, a generally triangular shaped control element rotatably mounted onsaid cylindrical plate, said triangular shaped control element having anoutwardly projecting portion formed so as to coact with said upwardlyprojecting portion of said arm, and a downwardly projecting portionadapted to fit into said notches in said indexing collar when saidupwardly projecting portion of said arm coacts with said outwardlyprojecting portion of said generally triangular shaped control element,said action occuring when said relay is energized.
 7. A slide projectoras claimed in claim 6 wherein said cam control mechanism includeS aforward-reverse relay operatively connected to said supply and storagecams so as to cause said supply and storage cams to rotate, whereby saidsupply and storage yokes are rotated.
 8. A slide projector as claimed inclaim 7 wherein said driving means also includes a gear mounted on saidshaft and coupled to said indexing collar and and a motor operativelyconnected to said gear for continuously rotating said gear.
 9. A slideprojector as claimed in claim 8 wherein said coupling means alsoincludes a second arm having an upwardly projecting portion operativelyconnected to said first arm, said first and second arms being mounted onopposite sides of said indexing collar so that their upwardly projectingpor-tions coact with the outwardly projecting portion of said generallytriangular shaped control element.
 10. A slide projector as claimed inclaim 9 wherein said cam control mechanism also includes a control plateand rotatable lever arms mounted on said control plate, said rotatablelever arms having pins that interact with out-wardly projecting portionsof said supply and storage cams, said interaction causing said supplyand storage cams to rotate into one of said two positions, said controlplate being attached to said forward-reverse relay so that said controlplate and said lever arms form a coupling between said forward-reverserelay and said supply and storage cams.
 11. A slide projector as claimedin claim 10 wherein said slide projector has supply, preview, projectionand storage posi-tions, said supply yoke being moveable between saidsupply and preview positions and said storage yoke being moveablebetween said projection and storage positions.
 12. A slide projector asclaimed in claim 11 wherein said lever arms are four in number, thefirst lever arm being adjacent said supply position, the second leverarm being adjacent said preview position, the third lever arm beingadjacent to said pro-jection position, and the fourth lever arm beingadjacent to said storage position, said lever arms being moveable bysaid con-trol plate into forward and reverse positions.
 13. A slideprojector as claimed in claim 1 wherein said slide projector has supply,preview, projection and storage positions, said supply yoke beingmoveable between said supply and preview positions and said storage yokebeing moveable between said projection and storage positions.
 14. Aslide movement mechanism for moving slides from a first slide magazineto a second slide magazine and vice versa comprising: a first yoke forengaging and moving a slide into or out of said first magazine, saidfirst yoke including means for pressing the second and subsequent slidesin said first magazine away from said first yoke when a slide is movedinto or out of said first magazine; a second yoke for engaging andmoving a slide into or out of said second magazine, said second yokeincluding means for pressing the second and subsequent slides in saidsecond magazine away from said second yoke when a slide is moved into orout of said second magazine; yoke control means operatively connected tosaid first and second yokes for moving said first and second yokes suchthat their means for pressing are moved into and out of engagement withthe second slide in said first and second magazines, respectively; and,transfer means operatively connected to said first and second yokes formoving said first and second yokes back and forth at right angles tosaid direction of yoke movement caused by said yoke control means sothat said first and second yokes are moved back and forth by saidtransfer means, and for moving said first and second yokes such thattheir said means for pressing are moved into and out of engagement withsaid second slides by said yoke control means as the first and secondyokes move a slide into or out of said supply and storage magazines. 15.A slide movement mechanism claimed in claim 14 wherein said transfermeans includes a generally rectangular slide transfer frame adapted toreciprocate back and forth in a path beneath said first and secondmagazines, said first and second yokes being rotatably mounted adjacentto the ends of said slide transfer frame.
 16. A slide movement mechanismas claimed in claim 15 wherein said yoke control means comprises; firstand second cams rotatably attached to said slide transfer frame beneathsaid slide transfer frame so as to project out-wardly therefrom; acontrol mechanism for selectively rotating said first and second camsbetween two positions in a prede-termined manner; and, cam faces formedin said first and second yokes adjacent to said first and second cams sothat when said first and second cams are selectively rotated back andforth between said two positions by said control means, said first andsecond yokes are rotated into and out of engagement with said slides.17. A slide movement mechanism as claimed in claim 16 wherein said slidetransfer frame includes a rail mounted at right angles to the directionthat said slide transfer frame reciprocates, said rail having a slot inits lower surface; and, wherein said slide movement means furthercomprises a cylindrical plate and a rotatable pin mounted on saidcylindrical plate, said pin projecting into said slot in said rail sothat the rotational movement of said pin is changed into reciprocatingmovement of said rail and said frame when said cylindrical plate isrotated, and a driving means for rotating said cylindrical plate.
 18. Aslide movement mechanism as claimed in claim 17 wherein said drivingmeans includes a notched indexing collar mounted on a shaft and couplingmeans for coupling said notched indexing collar to said cylindricalplate so as to cause intermittent rotational movement of saidcylindrical plate and said pin.
 19. A slide movement mechanism asclaimed in claim 18 wherein said coupling means includes: a relay; anarm having an upwardly projecting portion, said arm being operativelyconnected to said relay so as to be moved when said relay is energized;and, a generally triangular shaped control element rotatably mounted onsaid cylindrical plate, said triangular shaped control element having anoutwardly projecting portion formed so as to coact with said upwardlyprojecting portion of said arm, and a downwardly projecting portionadapted to fit into said notches in said indexing collar when saidupwardly projecting portion of said arm coacts with said outwardlyprojecting portion of said generally triangular shaped control, saidaction occuring when said relay is energized.
 20. A slide movementmechanism as claimed in claim 19 wherein said cam control mechanismincludes a forward-reverse relay operatively connected to said first andsecond cams so as to cause said first and second cams to rotate, wherebysaid first and second yokes are rotated.
 21. A slide movement mechanismas claimed in claim 20 wherein said driving means also includes a gearmounted on said shaft and coupled to said indexing collar and a motoroperatively connected to said gear for continuously rotating said gear.22. A slide movement mechanism as claimed in claim 21 wherein saidcoupling means also includes a second arm having an upwardly projectingportion operatively connected to said first arm, said first and secondarms being mounted on opposite sides of said indexing collar so thattheir upwardly projecting portions coact with the outwardly projectingportion of said generally triangular shaped control element.
 23. A slidemovement mechanism as claimed in claim 22 wherein said cam controlmechanism also includes a control plate and rotatable lever arms mountedon said control plate, said rotatable lever arms having pins thatinteract with outwardly projecting portions of said first and secondcams, said interaction causing said fIrst and second cams to rotate intoone of said two positions, said control plate being attached to saidforward-reverse relay so that said contRol plate and said lever armsform a coupling between said forward-reverse relay and said first andsecond cams.